The invention relates to a method for detecting interferences in a crop collection system of an agricultural harvesting machine, in which a crop stream is optically detected at the crop detection system.
Agricultural harvesting machines from the prior art, such as, for example, combine harvesters, comprise crop collection systems with which crop is intended to be picked up and fed to the further processing. Such crop collection systems regularly comprise a plurality of individual devices which can be operated using different parameters. In this way, the cutting height, position and speed of the reel as well as the movement of the cross auger and of the feeder, for example, of crop collection systems of combine harvesters can be adjusted. The ground speed of the harvesting machine also determines the quantity of crop that is picked up by the crop collection system.
Depending on the setting of the crop collection system and on the type, quantity, and properties of the picked-up crop, different types of interferences in the operation of the crop collection system can occur. One known example thereof is the occurrence of a crop blockage in the header of a combine harvester. If a crop blockage becomes fully formed, the harvesting process must be halted and a great deal of effort must be applied in order to eliminate the crop blockage. The time required therefor adversely affects the economic efficiency of the operation of the combine harvester.
More likely than not, such a crop blockage (or other interferences of crop collection systems) does or do not occur suddenly. Instead, the crop blockage or interferences build up over a relatively long period of time until a complete blockage occurs, which necessitates that the operation be completely interrupted. One problem associated therewith is that, by the time the complete blockage is readily and clearly detectable, it is already too late to correct the operation of the crop collection system, which also would have necessitated an interruption. Efforts are made to detect such a developing crop blockage or any other interference at an early point in time, so that suitable reactionary measures can be carried out. Such a reactionary measure might include temporarily reducing the present crop throughput, in order to avoid the developing crop blockage without necessitating the interruption of the harvesting operation.
DE 10 2008 032 191 A1 describes a self-propelled harvesting machine comprising a sensor unit for monitoring the crop stream within a front crop collection attachment of the harvesting machine. In particular, a camera is provided, which generates images of the crop stream. These images are subjected to an image-comparison process, in which the generated images of the crop stream are compared with reference images. By use of such a macroscopic comparison of the present image with the reference image, it can be ascertained whether the present crop stream deviates from the acceptable crop stream according to the reference image. In this case, one takes advantage of the situation that differences will become apparent in the present image, even as viewed macroscopically, when there is an increased amount of crop, for example, with regard to the portion and distribution of light versus dark ranges of brightness in the two images, etc.
A disadvantage of this approach is that it is based only on the simple presence of a difference between the reference image and the present image at the macroscopic level. This is too unspecific, on the one hand, since such a difference can occur in different interference scenarios, all of which can be detected, in theory, via the presence of a detectable difference, but which require a different and, optionally, opposing correction behavior in each case in order to be avoided or eliminated. In this regard, it is possible that the implemented reaction to the detected difference does not solve the problem, but rather worsens it.
Another disadvantage of the approach according to the prior art is that there are also interferences that cannot be detected, or cannot be detected early enough, on a basis of such a macroscopic image comparison.
Proceeding from this background, the problem addressed by the present invention is that of refining and improving the method known from the prior art for detecting interferences in a crop collection system with regard to accuracy, reliability, and timeliness.